Several joint projects involving different research groups are proposed which require the use of a recombinant DNA P3 facility. All of these projects have as their general objective, an increased understanding of the organiation and expression of specific eukaryotic genes. They all make use of cDNA probes prepared from purified or partially purified mRNA transcribed from these specific genes. It is proposed to clone these cDNAs in E. coli using recombinant DNA techniques so that large quantities of the probe can be obtained. One project involves the study of a gene for a specific light chain immunoglobulin and the post-transcriptional processing of the RNA which codes for this immunoglobulin. Another project involves a study of the molecular mechanism by which cAMP and hydrocortisone induce the synthesis of two hepatic enzymes, tyrosine aminotransferase and phosphoenolpyruvate carboxykinase. A third project investigates the molecular mechanism by which the antihistaminic drug, cyproheptidine, elicits a transient "diabetic" response in experimental animals still other projects explore the production of pituitary mRNAs which code for several of the small peptide hormones.